Method of forming dies



s. WADSTEN METHOD OF FORMING DIES Filed Jan. 12, 1928 2 Sheets-Sheet 1 INVENTOR STE/V MOSTEN May 27, 1930. s, w s 1,760,675

I IETHOD OF FORMING DIES F1136 Jan. 12. 1928 2 Sheets-Sheet 2 INVENTOR STE/v Mosrslv WME v ATTORNEY Patented May 27, l930 UNITED STATES PATENT OFFICE STEN WADSTEN, OF BLOOMFIELD, NEW JERSEY, ASSIGNOR TO WESTINGHOUSE LAMP COMP ANY, A CORPORATION OF PENNSYLVANIA METHOD OF FORMING DIES Application filed January 12, 1928. Serial No. 36,294.

assigned to the same assigneeas is the present application.

, In the above mentioned application, a machine is shown for coiling fine hair like wire to helical form in the absence of a mandrel and particularly for the production of such coiled wire to serve as filaments for incandescent electricv lamps. The machine shown comprises mechanism formoving a wire through a given path when tangentially engaged by a pair of oppositely disposed driving rollers which drive the wire endwise into a cavity die from which the wire issues in the form of a continuous helix. Means are also provided for cutting the helix into sections of proper lengths to constitute filaments for incandescent electric lamps.

The die is so arranged that the cavity is positioned to receive the wire from the driving rollers,'tlie bottom of the cavity being inclined or grooved so that.the wire is bent into a succession of coils which pass over a lip or separator member at the edge of the cavity. The helix or successive turns of the coil which issue from the die are consequently spaced a given distance apart and a helix is,

therefore, provided of a certain diameter and pitch depending upon the dimensions of the spacer member and the radius of curvature of the effective surface of the cavity as well as the position of the die with respect to the driving rollers.

In the manufacture of coiled filamentary bodies which serve as electrical resistance elements when used as lamp filaments, it is essenti al to exercise extreme accuracy in the formation of the coils, since each filament or coiled section must be made in accordance with specified dimensions so that each coiled sec tion will have a length of wire therein equal to the succeeding coiled section. F urthermore, the diameter of the coil as well as the spacing or pitch of the turns of the coil must be uniform.

The dimensions of the diameter and the proportions of the coiled sections vary for lamps of difierent wattage and the data relating to such dimensions and proportions. is known as the rating so that a coiled section for a given rating must be made in accordance with a predetermined set of dimensions. For example, a filament for a 60-watt 115 volt lamp must contain a length of wire of 517 mm., it must have a diameter of .0108

inches and the coiled section must contain 398 turns per inch. The diameter of the wire also varies in filaments of different wattage lamps and the diameter of the Wirev of a coiled filament of a watt lamp is prefer abl y .00187 inches.

It will be-obvious that in order to produce a lamp fila'ment'and hold the coil formation to the required proportions and dimensions it is necessary to accurately form the coil winding die and to provide accurately adjustable means forholding the said die in a given relation to the path of movement of the wire thereto, In the above mentioned copendingapplication, a coil winding die is shown and described as preferably consisting of. an extremely hard material such as a diamond. A diamond die, although having indefinite life, is diflicult to produce and owing to variations in the properties of a diamond, it is very often brittle to the extent that portions of the coil winding lip are broken off rendering the die inoperative for the purpose intended. As set forth in the said copending application, the coil winding die may be constructed from hardened steel but inasmuch as the wire passing over the die results in excessive wear,

into position for the winding of a'coiled filament, it is necessary to adjust the die in several planes until the cavity 1s accurately located in such position that the diameter and pitch of the coil produced will be in accordance with the data supplied for the rating of the particular lamp for which the filament is to befused.

, When using a. diamond die, the die re-- mains in the machine for such a long period that the amount of labor and inconvenience involved in a change from one die to another is negligible. A steel die, although easier to produce, must be changed at comparatively short intervals and the advantage given by the facility accompanying'the production of the die is lost' by the time and labor involved in replacing the same. 1 1

An object of the present invention is, therefore, to provide a method of producing a steel or other easily manufactured die having a coil winding cavity so arranged as to expedite the disposition of the cavity for a coil winding operation.

Another object of the invention is to provide a methodof producing a plurality of coil winding apertures adapted for substitutio one for the other.

Another object of the invention is to provide a coil winding die having a cavity so formed asto be disposed in accordance with the pitch of the coil to be produced.

Other objects and advantages of the invention will be more fully understood from the following description.

The invention may be practiced by provid ing a coil wound tightly upon a mandrel and with the turns of the coil in contacting rela tion-so as to make what is termed a closed coil. This coil may then be used as a primary embossing matrix and may be suitably supported so that a pair of die blanks in the form ofdiscs may be disposed with their edges or peripheries in contact with opposite sides of the coil. The blanks may then be rotated i the presence of sufiicient force to compress the blanks upon the embossing matrix during a movement of the blanks from the matrix 40' impression of the properly spaced coil. The

blanks ma then be hardened and employed as coil win ing elements, or dies in a mandrelless coil winding machine. f

The foregoing description briefly sets forth the general operation of practicing the present method which operation will be more fully understood'by reference to the accompanying drawings in which:

Fig. 1 is aside elevational view of a primary embossing matrix showing die blanks in contact therewith and partly in section Fig. 2 is a side elevational view of the secondary embossing matrix showing the die blanks in contact therewith partly in section;

Fig. 3 is a side view of a fixture for holding die blanks in position to be rolled. over a matrix during the application of a compressive force Fig. 4 is an end view of the fixture shown in Fig. 3;

Fig. 5 is a side view of a die blank partly broken away to show the depressions in the periphery thereof;

Fig. 0 is a side view of the die blank having a portion cut away to facilitate the use of one of the cavities or depressions of the blank;

Fig. 7 is an enlarged View of a portion of the die blank shown in Fig. 6 looking in the direction of the arrow X;

Fig. 8 is an edge View of a die blank after the depressions have been made therein and With a portion cut away; r

Fig. 9 is a view of a die blank similar to that shown in Fig. 8 but havin concave chamfered edges to accommodate the proper disposition of the blank in relation to a coil winding machine;

Fig. 10 shows a die positioned in operative The present method may beutilized by pro-' Viding a pair of disc like members 10 and 11. These members may be provided with suitable peripheral grooves 12 and may be provided with beveled edges. The blanks may be ofany suitable material such as relatively soft steel capable of being hardened. A suitable primary matrix may be provided by winding a wire 13 upon a mandrel 14 with the turns of the wire in contact so as to produce a closed coil 13'. The ends 15 and 16 of the coil may be held by clamps 17 and 18 of any suitable character.

The mandrel 14 may be supported in a holder (not shown) and the blanks 10 and 11 may be disposed so that the grooves 12 engage with the opposite sides of the coil 13. Two blank rollers or discs are employed inorder to balance the pressure and prevent asagging of the mandrel during the operation of impressing the coil into the peripheries of the blanks. For the purpose of applying force .fromwhich a spindle or shaft 22 may'extend' to receive the blank 10. The blank may beheld rotatably' in position by an end 23. The blank 11.may be mounted on a spindle 24 extendingfrom a slide plate 25 suitably held between guides 26 and 27 secured to the fixture 19 The blanks 11 and 121 may be disposed in the. same plane with the grooves of their peripheries arranged to receive the coil winding. periphery may be ground to coiled wire 13.

When the said blanks are in position at 36 and 37 which contact with a wire 38 to be opposite sides of the coil'13' a relative movedriven into a die to produce a mandrelless ment may be effected between the coil and the coiled section 39. blanks to cause a rotation of the blanks and After the operation of forming the depresat the same time a force may be applied by sions in the blanks has been performed, the turning a set screw 28 extending through a blank is provided with a plurality of coil base portion 29 of the fixture 19. The set winding depressions 40, each of the blanks screw may be provided with a collar 30 to prebeing similar and constituting a die-member ven't endwise movement of the set screw and 41 as. shown in Fig. 5. The die-member 41 a threaded end 31 of the set screw may enter may be employed as a wire bending element a threaded aperture 32 in the slide 25 so that by utilizing one of the cavities 40 and a ridge a rotation of the set screw will cause the slide 42 as a spacer member for the coils. By and consequently the roller 11 to be moved holding the die-member 41 in position so that to or from the roller 10 and thus the wire the wire 38 is driven against the cavity 40, the between the rollers may be compressed. coils will issue from the cavity and be spaced It is obvious that itis immaterial whether by reason of the ridge or lip 42. It has been the fixture 19 is moved tocause a rotation of found preferable, however, to cut away a porthe rollers over the coil or whether the coil tion of the die-member as shown in Fig. 6,

itself is reciprocated along its longitudinal leaving the lip or ridge 42 with a shorter face.

axis. It has been found, however, preferable 43 so that the coils when issuing from the deto mount the mandrel supporting the coil pression 40 will more readily escape from in a lathe. s the die.

In practicing the invention, it has been It will be evident that by reason of the found that manufacturing conditions are met plurality of depressions provided in the dieby performing the method in the following member, each depression constitutes a die successive operations. For example, a die bending surface and upon the failure of one' for a 10' watt lamp may be made in accord-' as by wearing or breaking, another may be diameter is used and wound on a steel manance with data calling for a coil of .004 of an utilized by either moving the die-member 41 inch outside diameter having 1000 turns per or, by grinding away the face 43. It will be inch. formed from a wire of .0006 of an inch further appreciated that inasmuch as the dein diameter. In order to make a die for a pressions. are formed exactly in, accordance coil in accordance with the above mentioned with the pit h f h m n r COil. to be data, a tungsten wire of .00099 of an inch produced that a more accurate and uniform Lwinding in so far as diameter and pitch are drel of .0025 of an inch diameter so as to proconcerned will be produced. duce a coiled section with the turns of the The die-member 41 may be used in the coil in contact or what may be termed a, form as shown in Fig. 8 in which the edges of closed coil. In producing th id l d the die have a tapered or chamfered face 44. coil, a mandrel type coiling machine is em- The -m mber, however, maybe mademore ployed which is said to obtain 1000 turns per effective for the @011 wlndlng operation by inch and the coiled sections produced should g g the edges 34 and 35 to a radius as be about 3 feet in length. This coiled sec- Shown iIlFigs. 9, 1 0 and 11 S0 a the dietion is what is termed the primary embossing member y e moved In o e relatlon to matrix. This embossing mat i 13 me the tangential pointof the driving rollers 36 then be held in position so that the die'blanks and 7 Which constitute P Of the 11 Wind- 10 and 11 may be rolled thereover, Aft ing machine set forth 1n the above mentioned each movement of the die blanks over the p f g pr e coil, the pressurebetween the coil and die It 18 0133710115 the dlejblank y be blanks may be increased until an appreciable m of y sultable matellali as depression is produced i th bl k ample, soft steel WlllCh may be hardened as After the completion of th operation f aboveset forth or the said blank may be of forming the die blanks, another coiled section a sof material w W111 arden a ter the is produced with a left hand windi g d pressing operation as, for. example, a soft made in accordance with the pro er oil heated material which hardens upon cooling. winding data. This second wound coil is Furthermore, the blank need not be a disc, spaced to the proper pitch and is termed the ut may be inthe form of a bar or block secondary matrix 33 as shown in Fig. 2. The which may be pressed into contact with the operation of rolling the blanks over the coil coil forming matrix.

is performed in the same manner. as above The present method, therefore, provides described for the initial depression taken for the manufacture of a coil winding die from the primary matrix 13'. The blanks in a conyenient and expeditious manner at may then be hardened and heat treated and comparatively low cost. The die produced the edges 34 and 35-of the blanks adjacent the has long life by reason of the multiplicity provide clearance for wire driving rollers of coil winding surfaces and is easily adjustable to substitute one surface for another.

Although a preferred embodiment of the invention is shown and described herein, it is to be understood that variations and modifications may be made therein without departing from the spirit and scope of the invention as set forth in the appended claims.

What isclaimed is:

1. The method of producing a coil winding die which consists in supporting a heli-' cally coiled section of Wire having the turns thereof in given spaced relation, moving a blank having a curved surface in contact with said c011, applying a force to produce an initial impression of said coil in said blank and in moving-said blank into contact with another coiledsection having the turns thereof in a different spaced relation.

2. The method of producing-a coilwinding die which consists in supporting a coiled section, disposing a disc-shaped blank in contact with said coiled section of wire of a given diameter and having the turns in given spaced relation in moving said disc over said coiled section in the presence of an applied force to produce an initial impression of said coiled section'in said blank and in moving said blank into contact with another coiled section of wire of a different diameter and having the turns thereof in a different spaced relation.

3. The method of producing a coil wind- I STEN WADSTEN.

of helically coiled wire having the turns of a given space relation, moving a blank into contact with said coiled wire to produce an initial impression in-said blank and in moving said blank into contact with a coiled section having the turns of a different space relation to increase the depth of said depression'and, produce a'pitch in accordance with the second mentioned coiled section of wire.

4. The method of producing a coil winding die which consists in supporting a coiled section of wire of a given pitch with the turns of wire in a given space relation, moving the periphery of a disc-shaped blank in contact I with said coiled section in the presence of an applied force to produce an initial depression in said blank, moving said blank into contact with a coiled section of a similar pitch but. with turns of a different space.

:i'elation in the presence of an applied force to lncrease the depth of said first depression tact with said coiled section in the presence of an applied force to roduce an initial depression in said bla moving said blank 

